THE CURRENT STATUS OF ANALYZING HIGH-DEGREE MODES

摘要

One of the most glaring issues in contemporary helio-seismologyrnis the rather limited availability of both high-degreernmode frequencies for use in inversions of solarrninternal structure as well as of high-degree frequencyrnsplittings for use in inversions of solar internal dynam-ics.rnThe lack of high-degree frequencies and frequencyrnsplittings has occurred because of the inherent difficul-tiesrnin measuring such frequencies and frequency split-tingsrnin high-degree spectra without the inclusion of nu-merousrnsystematic errors. After the discussion of bothrnthe importance and the problems inherent in the analysisrnof high-degree modes, we describe some fitting method-ologiesrndeveloped since the mid 1990s to obtain high-degreernmode characteristics. Finally, we present ini-tialrnresults from the inversion of high-degree modes ob-tainedrnwith our newly developed multiple-peak, tesseral-spectrumrnmethod to demonstrate the potential of high-degreernmodes in the helioseismic probing of the outer-mostrnlayers of the Sun. All results reported are basedrnupon data taken by the Michelson Doppler Imager (MDI),rnwhich is onboard the Solar and Heliospheric Observatoryrn(SOHO), operating in its full-disk mode during the 1996rnDynamics Run.